The most favorable property of organic optoelectronic devices such as organic light-emitting diodes (OLED), organic photovoltaic (OPV), organic thin film transistor (OTFT), and organic semiconductor lasers (OSL), is that they are flexible. The organic optoelectronic devices can be made with a flexible polymer substrate such as polyethylene (PE), polypropylene (PP), polystyrene (PS), polyethersulfone (PES), polyethylene naphthalate (PEN) and polyimide (PI). The polymer substrate enable the organic optoelectronic devices to be flexible and rolled into arbitrary shape.
An organic optoelectronic device is very sensitive to the water and oxygen erosion, and trace amounts of water and oxygen will cause oxidation, crystallization or electrode degradation of organic materials in the device, which will affect device life or lead directly to the failure of the device. Compared with glass substrate, the water or oxygen transmittance of the most polymer substrate is relatively high to be not enough to guarantee the device keep long term reliable operation. The water permeation rate and oxygen permeation rate of common polymer substrates are shown in the table below.
PolymerWater Permeation RateOxygen Permeation RateSubstrate(g/m2 · d) 37~40° C.(cc/m2 · d) 20~23° C.PE1.2~5.970~550PP1.5~5.993~300PS7.9~40 200~540 PES140.04PEN  7.33.0 PI0.4~21 0.04~17  
In the prior art, the polymeric substrate is generally alternately provided with a planarization layer and a water and oxygen barrier layer to increase the water and oxygen barrier capacity of the polymeric substrate. As shown in FIG. 1, water and oxygen barrier layers 103 are provided on the polymeric substrate 101 and separated by a planarization layer 102. The water and oxygen barrier layer 103 is used to isolate water vapor and oxygen, and a planarization layer 102 is provided between the adjacent water and oxygen barrier layers 103 in order to guarantee the compactness and smoothness of the film formation and inhibit the growth of the defect in the film. Generally, three to five or more water and oxygen barrier layers 103 should be provided on the polymeric substrate to have the water and oxygen barrier capacity adapted to produce organic optoelectronic devices. However, the planarization layer 102 is generally a polymer material layer, which has a poor water and oxygen barrier capacity, and when the polymeric substrate has to be cut, the side surface after cutting will be exposed to the external air that the water vapor and oxygen will infiltrate into the device along the path indicated by the arrowhead, so that there is only one oxygen barrier layer 103 playing a barrier role, which seriously influences the performance of the device.
To solve this problem, for an existing flexible substrate, it has to define the size of the substrate at first, and then define the coverage areas of the water and oxygen barrier layer and the planarization layer based on the size with making the coverage area of the planarization layer smaller than that of the water and oxygen barrier layer, so that multiple layers of water and oxygen barriers can be connected with each other on the edge of the flexible substrate to prevent the water vapor and oxygen from infiltrating from the side. However, this solution brings a problem that the prepared flexible substrate cannot be cut to meet to the requirement for different product sizes, and the product with a different size needs a set of masks adapted to its size to define the sizes of the planarization layer and the water and oxygen barrier layer, which undoubtedly increases the production cost.
In addition, roll-to-roll coating is known as an efficient means for ramping up the production capacity of the flexible substrate with water and oxygen barrier films and reducing production cost, but the technology must involve a process of cutting, the roll-to-roll is unsuitable for the above preparation method for water and oxygen barrier films, thus the production cost cannot be effectively reduced.